I dont know anything about medical coding as a profession. But I can tell you to choose your school carefully. A very high percentage of the "schools" promoting training specific fields such as medical coding, dental hygenist, medical assistant, etc are merely in the business of procuring loans for their students. Education is not the goal, they exist to make money.
Check with some of the employers you plan to target after you receive your certification and ask them if they have a recommendation for an educational path. Or if the certificate is of any advantage when they are hiring.